The present invention relates to a technique for managing storages by a file system in a computer system, and more particularly to a technique for managing storage power in a large-scale computer system.
With an increase in the amount of data processing in a computer system, storages are becoming large-scale. Some large-scale computer systems have storage devices from several hundred TB to several PB, so that power consumed by the storages is becoming unignorable.
On the other hand, in the above-described large-scale computer systems, access to all storage devices does not occur continuously throughout a year. For example, large-scale computer systems are lent to users on an hour basis, and access to storage devices in which files owned by the users do not exist is rare.
Accordingly, according to a known technique as described in JP-A No. 2007-133821, in a storage in which a physical storage device that can control activation and halt, and a physical storage device that cannot control them coexist, properties are taken into account to set logical storage devices on the physical storage devices and thereby to reduce power consumption of the storage. According to this technique, when access to the logical storage devices set on the physical storage devices is stopped, it is determined whether the physical storage devices can be halted. When they can be halted, they are halted, and otherwise, the logical storage devices are moved to a physical storage device that can be halted, and the physical storage device is halted.
Furthermore, according to a known technique as described in JP-A No. 2007-164650, based on access situation, logical storage devices are moved among physical storage devices having different power supply modes to reduce energization time. With this technique, the relocation of the logical storage devices is scheduled so that logical storage devices frequently accessed are located in physical storage devices of long energization mode, and logical storage devices infrequently accessed are located in physical storage devices of short energization mode. The logical storage devices are relocated based on the frequency of access to the physical storage devices.